Removing White Hazy Marks From Glass

[Seppi72]

Carguyinok:

Wow. It makes no sense to me that anyone would make laminated glass for anything other than the windshield (W/S in glass lingo). The cost of laminated is at least 4 or 5 times that of the equivalent tempered part.

In addition, I'm not sure that laminated backlight (B/L) glass could handle the heat produced by the defroster grid without serious issues. The plastic in a laminated part is polyvinyl butyrate (PVB) and PVB absorbs moisture. It, therefore, has to be dried before the lamination process or else the heat required to get it soft and sticky so that it glues the two plies of glass together will cause the formation of bubbles (from the absorbed water). After manufacture, and over time, the PVB will reabsorb moisture along the exposed edges of the part unless they are sealed off from the atmosphere during the installation process. If the saturated PVB gets heated above, say, 200 F, you will see bubbles form again. And the local temperature of a defroster grid wire is well above that threshold.

As for identifying glass, there will be a mark or logo in the lower corner of every piece that gets put on a car destined for the U.S. (and probably most other first-world countries) that identifies the maker and whether it is AS1 (Approved Safety type 1 = laminated) or AS2 (tempered). I can't recall who made the OEM glass for the 240Z, but it might have been NSG (Nippon Sheet Glass Co, Ltd.). I DO know that all OEM glass was made in Japan so if you see a PPG logo or something else, it's aftermarket or AGR (automotive glass replacement).

Sorry about all the abbreviations, but I spent the time to learn them and I don't get too many chances to use them anymore.

[Mike B]

What do I look for on the glass that would tell me that it's stock glass?

The word NISSAN.

-Mike

[carguyinok]

Thank you, I thought it would say Nissan but wasnt 100% sure on that. I will see if I can get some photos of them up. For now I am just going too use the glass from my 73 in the back. Thank you on the info Bob. I dont understand how or why. The rear glass has bubbles near the edge in the corners. But the windshield is the one that stinks for me. It's 100% no chips or cracks. Yet it has a fog and bubbles in front of the driver just at the view point.

So, is one windshield brand better then another in todays market?

[Seppi72]

I described my issues with AGR W/S parts in another thread a month or so ago but here's a reprise.

Las year, I bought a W/S from Black Dragon. It was PPG band but marked made in China. The damn thing broke on me while I was storing it. Afterwards, I checked and the glass plies were considerably thinner than I believe they should have been. At least when I was at L-O-F and we were making such parts for both OEM and AGR channels, the glass was thicker.

I would call a couple of your local glass suppliers and see what brand they can get, the cost and, importantly, the construction; meaning the thicknesses (in mils) of the glass/PVB/glass sandwich. It should be something like 80/30/80. Even better is 90/30/90. The two glass plies are "always" the same thickness as it doesn't make sense to use differing thicknesses considering how the parts are made and how they have to match up. I'd bet that the Chinese PPG W/S (long ago trashed) was a 70/20/70 - the b*st*rds.

Call up Black Dragon too and ask them for the make and construction of the W/S parts they have in stock now. If they claim they can't do that, tell them to measure one ply and then the overall thickness. You can deduce the construction from that assuming equal ply thicknesses.

I'd be curious to know all this info as I STILL need a freaking W/S for my rebuild project.:stupid:

[hls30.com]

Are you sure it's on the outside of the glass? I have three windows on my 240 that are going bad inside. They have a white haze or fog with it aswell. What is happening is safty glass is 2 sheets of glass with a clear rubber between the two parts. Over time with sun and heat that rubber can go bad. When that happens you can get a milky look and little bubbles over time.

If thats the case your only fix is new glass.

If you can feel it on the glass then it can be removed. If thats the case you can get it off with a very very fine steelwool and glass cleaner. Just MAKE SURE the glass is wet!!! I have owned detail shops in the past and no that will not scar the glass. We steel wool every window that we are putting tint on aswell and have NEVER left a scar or scratch behinde.

I hate to tell you, but if a steel blade will scratch glass, steel wool will. Even the makers of Brillo pads admit that unless there is soap on the glass, steel wool should not be used on glass. More importantly, steel wool will shred into fibers that will get into the seams of the area and rust, potentially causing all kinds of problems. Use Brass wool and it will not scratch glass, rust or cause problems with paint, weather seals, or wipers.

Will

Edited March 2, 2009 by hls30.com